Saturday, September 4, 2010

Reptiles: Adirondack Turtles

I love turtles. I know, it seems I start a lot of articles with expressions of extreme admiration for whatever the featured species is that day. What can I say – I find nature to be endlessly fascinating. That said, I think turtles are special, and the more I learn about them, the more amazing they become.

On the surface, we all know that turtles are animals with shells. They plod along on land, or swim gracefully in the water. Some live in the oceans, some in the deserts – what wonderful extremes they have come to inhabit. They have been around for over 200 million years – since the late Triassic. Some species can live well over a hundred years. Digging deeper, though, we find even more fascinating information.

Four species of turtles live within the Blue Line: snapping turtles, wood turtles, painted turtles (eastern and midland species), and Blanding’s turtles. Let me share with you a little bit about each of these species before detouring into some generalized nifty turtle traits.

Snapping turtles, those truly dinosaurish turtles, are probably the turtle we see most often. Every spring the females leave their watery homes in search of the perfect sandy spot in which to dig holes and lay eggs. Most of these eggs will be eaten by predators, but the survivors hatch by late summer. Sometimes the newly hatched turtles leave the nest immediately, while others opt to remain in the relative safety of the nest over winter, which explains why baby snappers are found on the move in both the spring and the fall. When they aren’t out searching for nest sites, these turtles are most often lying low in the muddy substrate of shallow, slow-moving waters, which is why their shells are “mossy” – these turtles are not baskers. Despite the apparent commonness of the species, recent population studies show that snapping turtles are in decline across New York State, mostly a result of fatal encounters with motorized vehicles.

Wood turtles are close to my heart. I see them every spring as they, too, search for perfect nest sites along the sandy shoulders of our roads. Their populations are considered sporadic, possibly because they are terrestrial and often on the move. One of our larger turtles, the wood turtle stands out among its brethren on two accounts: it has brilliant orange markings along its neck, forelegs and tail, and it is considered to be quite intelligent. Sadly, these turtles are frequently exploited in the pet trade, which compounds their losses to fast-moving traffic.

I know we have painted turtles in the Park, but I seldom see them. Most likely this is because they like particular types of wetlands, of which I am also quite fond, but I don’t get into them nearly enough to encounter painted turtles on a regular basis. Common and widespread, the painted turtle is the one we all know by sight: dark with red and yellow lines “painted’ along its neck, legs, tail and shell.

Our fourth turtle is the Blanding’s. This may not be a species most people have heard of, which isn’t too surprising. In New York it is a threatened species; I’ve only seen two in my life, both of which were in captivity. The first had been hit by a car and the facility where I was working was taking care of it until it could be returned to the wild. The second, which I saw this summer, was a “pet” belonging to a herptetologist. Blanding’s turtles are on the largish end of the land turtle scale, smaller than the snappers, but comparable to wood turtles. What stands out about these turtles is their highly domed shells and their yellow chins. If necessary, the Blanding’s turtle (named for William Blanding, by the way, a physician and naturalist from Massachusetts, who collected the original specimen in 1830) can close the front end of its shell, ala box turtle, for protection. (Box turtles can actually close both the front and back ends of their shells.)

And now, some of the fascinating things we should all know about turtles.

First, it takes an awfully long time for a turtle to become reproductive (ten or more years). It is currently believed that this is because after birth young turtles put most of their energy into developing their shells. The turtle’s shell is its means of protection, and until the advent of the motorized vehicle, it served the animals well. Once completely developed, the turtle’s shell is a formidable defense. There aren’t too many natural predators that can kill a turtle. A good shell, therefore, is imperative to survival; offspring can come later.

Next, there’s the method by which a turtle breathes. Like reproduction, a turtle’s breathing is tied in to its shell. Anyone who has seen a turtle shell sans turtle has noted that the animal’s ribs are fused to the inner carapace (the carapace is the upper portion of the shell; the plastron covers the belly). You and I manage breathing because our rib cages can expand with our lungs. Not so the turtles. Instead, they have a special musculature that, as so eloquently put in The Reptiles and Amphibians of New York State, “ sloshes the internal organs back and forth to draw air in and out of the lungs.” Curious about this, I did a little more digging. One set of respiratory muscles pulls all the internal organs outwards towards the edges of the shell. This allows the lungs, which are located near the top of the shell, to fill with air. The second set of muscles pushes everything back inwards, pressing against the lungs to expel the air. How wonderfully adaptive!

Temperature affects sex. That is, temperature determines the sex of the animal . When I first learned this, I thought it was just amazing. It seems that the warmer eggs develop into females, while the cooler eggs, which tend to be toward the bottom of the nest, develop into males. Depending on climate, some years nests can hatch out mostly female turtles, while other years the balance tips in favor of males. Will climate change affect this? If most nests yield females, how will our turtles find enough males to reproduce? Interesting question.

It breaks my heart that so many species of turtles are in decline. We (as a species) eat them, capture them for the pet trade, toss them aside as by-kill in the fishing industry, and run them over with our cars. Their homes are lost to development and pollution. I sometimes wonder if this ancient line of animals, who have survived so much, will ever survive humans. So, perhaps it isn’t too surprising that I experience great joy every time I see a turtle.

Wild turtles shouldn’t be pets, and pet turtles, which may not be native species, should not be released into the wild when the novelty wears off. If you see a turtle trying to cross the road, slow down – don’t run it over. If traffic is slow, pull over and assist the turtle in its journey. Never pick a turtle up by its tail (I don’t care what popular belief is – this can/will injure the turtle). Be cautious around the business end of a snapper – its name is well deserved.

I encourage everyone to enjoy turtles, and with a little common sense, it is easy to do.

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Ellen Rathbone

Ellen Rathbone is by her own admission a "certified nature nut." She began contributing to the Adirondack Almanack while living in Newcomb, when she was an environmental educator for the Adirondack Park Agency's Visitor Interpretive Centers for nearly ten years.

Ellen graduated from SUNY ESF in 1988 with a BS in forestry and biology and has worked as a naturalist in New York, New Jersey, and Vermont.

In 2010 her work took her to Michigan, where she currently resides and serves as Education Director of the Dahlem Conservancy just outside Jackson, Michigan.

She also writes her own blog about her Michigan adventures.





3 Responses

  1. Emily DeBolt, director of education, Lake George Association says:

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